/Engine/Source/Runtime/GeometryCore/Public/Spatial/SpatialInterfaces.h
ID of triangle nearest to Point within MaxDistance, or InvalidID if not found
int FindNearestTriangle ( const FVector3d & Point, double & NearestDistSqrOut, const [FQueryOptions](API\Runtime\GeometryCore\Spatial\IMeshSpatial\FQueryOptions) & Options ) const